Art of refining hydrocarbons



Jan. 12, 1932. F; A. APGAR ART OF REFINING HYDROCARBONS Filed Feb. 10, 1928 2 Sheets-Sheet S MrW W MW m w /Mm N T .14 A M Jan. 12, 1932. A APGAR 1,841,271

ART OF REFINING HYDROCARBONS Filed Feb. 10, 1928 2 Sheets-Sheet 2 d in I h AT 'l ORNEY6;

Patented Jan. 12, 1932 ;UNI ED+.srarss Ana: ossmmm nYnnocansons Application filed Februar 10', 1928. Serial no. 253,513.

This invention relates to improvements in bricatingoils which has'several important general advantages andKwhicli" has several special advantages in special applications.

According to the present invention, an oil.

containing the desired lubricating oil fraction is heated in a still and vapors of the lubricating oil fraction are driven ofi', the pressure on theselubricating 011 vapors 1s reduced to a value substantially less than atmospheric pressure, the lubricating oil vapors while under this sub-atmosphericp'ressure are passed through a body of fullers earth or some similar adsorptive catalyst,

and, after passage through the fullers earth,

the vapors are condensed to-forma finished lubricating oil distillate; V The pressure in the still where the lubricating oil fraction is initially vaporized may be atmospheric, super-atmospheric or. sub-atmospheric; The pressure under which the vapors are passed a through the fullers earth may with advantage approximate to 8 inches of mercury absolute; pressures below about inches of mercury absolute are generally useful in carrying outthe invention. The operation is with advantage carried out as a continuous operation. The invention includes improve ments in the'refining operation proper as well as improvements in thecombined distilling and refining operation. a

Hitherto, it has been customary to refine lubricating oils by treatment withvarious chemical refining agents, suclr as'sulphuric acid and caustic alkali solutions. Lubricatingoils are viscous and usuallyrelatively dense. Also, they frequently tend to form more or less stable emulsions with'water or aqueous solutions of refining agents and with sludges resulting'from' treatment ,withsuch agents. hese and other peculiar prop erties of lubricating oils make such refinin operations quite critical. The close control required involves diflicultieslwhich are emphasized because of the relatively high.

value of the oil product-under treatment. This invention avoids thedifliculties ofithese ii H FRANK A. APGAR, or nasr-enronooymnmna, assrcrnoaro snvonarn aiirrnme n customary methods. The control (iquirea is not critical. Such chemical refining-agents are-notfrequire'd. Any possibilityof contam -f inatingthe lubricating oil product with such chemical refining agents is-avoided. 1 Loss;

of valuable lubricating oil COIIIPOII l h I refining 'slugesis avoided." IThe overall losses of lubricating oil are very small. Afinishe'd lubricating oil product maybe producedfdi rectlyinasimplified operation from asphalt base cru'degstocks The production of finished lubricating oil products from *wax containing stocks. maybe much simplified.

As applied to wan-containing;stocks, the in vention has moreover severalspec al advan tages. 7

Lubricating 011 diseases iiom' arafiifie baseormixed base crude stocks usuallyconf tain in solutionaquantity of Wax. Theform" in Whichthis waxsep'arates fromthe oil vari es anddepends upona number of, factors many of which are notyet fully understood, On chilling, such dissolved wax may separate in a so-called amorphous state or it may separate in a crystalline state. Until quite recently this phenomena ;has' been explained by assuming two types of wax, an amorphous wax anda crystalline wax; Recently however there is a growingbeliefthat all wax is crystalline but that in thepre'sence of some protective colloid or crystallization inhibitor In any it separates in an amorphous state. event, wax separating in a crystalline state is handled much'more easily than Wax separating in an amorphous state and several expedients have been used to promote separa tion of dissolvedwax in a crystalline' state For convenience of reference,- wax present under conditions such that it tends to .separate as crystalline "wax may be designated fpotentially. crystalline wax and 'waxpresi ent under conditions such that it tends tosep-f nated potentially amorphous wax]? i V Hitherto, it has been customary to separate .arate as .amorphousbwax may be desigpotentially crystalline wax by first chilling the oil and then passing the chilled oil through filter presses to separate the result ing wax crystals, a reasonably simple and inexpensive operation. But the usual filter presses cannot handle potentially amorphous Sill wax. It has been customary to separate potentially amorphous wax by diluting the oil witha low boiling solvent, chilling the mixture, settling or centrifuging the wax from the mixture, and distilling the lowboiling solvent. from :the 'niixtr e. To avoid this more complex and more expensive operation, lubricating oil stocks containingpotentially amorphous wax have commonly been subject- 7 ed to a mild cracking to convert potentially amorphous wax to potentially crystalline to permit separation in the manner first described. vThis cracking, however, tends toreduce the viscosity of the oil and make its color less desirable, so that the lubricating oils so produced are not usually as valuable as those 'proelucedifiwithont cracking. This invention provides aTpartic-ularly advantageons method zoteonverting potentially amorphous wax to potentially crystalline wax permitting ready separation lay-chilling and filter pressing of the'refined oil. 1 I

VY "hcrrthe' pressure on the vapors passing tromthevapori-zing operationto the refining operation proper'is reduced, in carrying out the present invention, the vapors are superheated as a consequence. This feature of the invention has several special advantages. It promotes long lifeof the adsorptive catalyst used in the refining operation. It renders theiadsorptive catalyst more effective for its intended purpose, :that'is the refining of the lubricating .oil product, perhaps because this superheating of the vapors reduces condensa tionin the catalyst body: or adsorption by the catalystot lubricating oil constituents which might otherwise reduce the life or power of the catalyst. Further, due to this superheatinvention is not critical, as-noted above. For

example, si es the boiling temperature of a liquid increases within'crease of pressure, the temperature of the vapors driven ofi in the vaporizing-still is fixed'by fixing the pressure in that still without requiring further control and the temperature of the vapors passing through the adsorptive catalyst is fixed by fixing t the differential between that pressure and the lower pressure in the refining operation prophe pressure in the vaporizing still and ,er. The pressure in the vaporizing still may be substantially atmospheric pressure or may somewhat exceed that value, or if the temperature prevailing at such pressure involve objectionable cracking the vaporizing still may be operated under a pressure sufficiently below atmospheric pressure toavoid such objectionable cracking. Thetemperatures determined by the pressures described, in the treatment of lubricating oil fractions, are particularly advantageous in the combined operation of the invention as well as in the refining operation proper.

The inventionwill be further described in connection with the accompanying drawings which illustrate, diagrammatically and conventionally, apparatus adapted for carrying out theinvention, The .exact form of apparatus illustrated is not essential to the invention, but-the apparatus illustrated is advantageous for carrying out the invention and'itisused for illustration of the invention for that reason; ings; Fig. 1 represents, in elevation and partly in section, one form of apparatus adapted for carrying out the invention, and Fig. 2 represents, similarly, another form of apparatus adapted for carrying out the invention.

Referring to Fig. 1, the apparatus illustrated comprises a still 3, a reflux tower 4, a refining tower 5, a condenser v6, a receiver 7, and an exhausting pump 8. The reflux tower 4 is of the type described and illustrated in anapplication of John E. Bell, filed April 1, 1924, Serial No. $703,338. When the valve 9 is opened, vapcrsftrom the still pass upwardlythrough thextower 4, vapors reinaining-uncondensed escapethrough c'onnec tion 10 to a condenser and receiver and reflux condensate. together with any unvaporized portions of oil introduced into the tower, flows back to the still through connection 11. Connections 12 and 13 are provided for introduction of oil into-the upper end of tower 4. Connection 14 is provided tordraining the tower, or by closing the valve in connection 11 and'opening the valve in connection 14 condensate produced in the tower may be discharged without being returned to the still. Connection 15 is provided for the discharge of residual oil from the still. The still 3 maybe a fire heated still or a steam heated still or it'may be a fire heated still with pro vision for the introduction of steam into the charge of oil therein. When the valve 9 is closed and the valve-16 is open, vapors from the still escape through connection 17 to and through the refining tower 5. Vaporsescaping from the refining tower 5, through connection 18, are condensed in the condenser 6, the condensate being discharged into receiver 7. The refining tower5, the condenser 6 and the receiver 7 may be maintained under sub-atmospheric pressure by means of the Inthe accompanying drawpressure reducing I valve 16 and the exhaust- 7 ing pump 8. Pump 19; is" providedgfor the discharge of condensatethrough'connection 25' when the receiverv F phericpressure. Anyvmaterial liquefieddn 1 is under sub-atmosthe refining tower 5 is run toa storage tank 20 by means of pump 21', either directly;

and the connections 17 and 18. A chargeof an adsorptive catalyst, for exarmole, fullers earth of 410 60 or 60-80 mesh, is supported upon a 'foraminous partition-24 adapted to retain the adsorptive catalyst but to permit free passage of vapors through the refining tower 5. V In one way of carrying out the invention in the apparatus illustrated in Fig. l,'a crude petroleumior a topped crude petroleum or other lubricating oilstock is first stripped of constituents lighterq'than suitable" as "com ponents of the desired'lubricating.oil product, vapors ofthese lighter constituents being separatelytaken off and condensed,-fandas the lubricating oil vapors begin to comelofi they arediverted through the refining tower where the latter are subjected to'refiriing treatment in accordance with the invention under sub-atmospheric pressure; vThe distillation operation, for example,"may be car ried out as described in an applicationxof Edward W. Isom, filed May 6", 1924, Serial N0.711,3'Z6 m a t The following example will illustrate mode of operationEThe: still is. initially charged with from one third to one-half of the normal operating charge'ofthe" lubricating oil stock and, withvalve l6 closedand valve 9open,-thischarge is heated until the lighter constituents of the initial' charge have been vaporized anddriven. off through connection 10. -A low' boilingfractiom for example, a: part of the condensate product from the vapors escaping through connection 10, may be introduced through connection 12 to control the operation. The further in; troduction of the lubricating oil stockisithen begun through connection 13.-whi1e .theiheat ing is continued The rate ofz introduction of the lubricating oil, stock through connection 13 is regulated to control the refluxing operation so that only the lighter constituents ofthe stock are permitted to "escape through connection 10. Thiscontrol may be; supple mented by the regulated introduction of a lower boiling fraction, for example, apartof the condensate produced from the vapors escaping through connection 10, through connection 12. Gasoline, kerosene and gas oil components of the lubricating'oil stool? are stripped from it in-this manner. As the dis tillation continues, a charge of oil containing the lubricating oil constituents of'the stock I but free from lighter constituents accumu lates in thestill' 3. Beforefthe charge of oil I,

in th'estill 3 becomes excessive, the introduc-- tion of oil to'tower l is stopped, the valve 9 is closed and, the exhausting pump 8 being i in operation, the valve-16 is openor partly opened,'the opening of the valve 16 being rege ulated to maintain the desired "sub-atmo'sk I pheric pressure in the refiningtower 5;; The

heating is continued and the lubricating oil I constituents of the still charge are vaporized and driven oil through connection 17. 'These lubricating oil vapors are passed through the fullers earth in the refining-tower5 under sub-atmospheric'pressure andthe vapors ofthe refined lubricating'oil escaping from; the

refining tower are" condensed in the con},

denserfi to forma lubricating oil product dis charged throughconnection 25.

If theglubricating oil stock treatedmanner just'described contains lwax'ythe discharged lubricating oil productv isflchilled and put through filter presses for the separation of such wax. This separation is readily efiected because of the conversion of potentially amorphous wax to potentially crystalin the line waxeliected in carrying out the invention, *It'will be apparent that this mode of o operation makes possiblethe production, of

finished lubricating oil products from waxcontaining stocks withoutre-running ofa di luted stock and without any necessityforsub 'jecting the stock tomild cracking as thatop- I, eration is commonly carried out insO-Called ;coke stills." t I V Referring toFig: 2, the apparatusillustrated comprises a still 33', a refining tower 35, a condenser'36, 'a'receiver 37 and an exhausting pump 38.- The sti1l33 may be a fire heated still or a steam heated still, for example, as by steam eoi1'34, or itmay beta fire heated still withprovision for the introductionof the steam into the "charge of oil thereinfl' This still 33isadvantageously arranged for continuous operation as a single unit or as one unit in a -battery of cQntinu ouslyjoperat ed stills. In continuous opera-, tion, the raw'stock including the desired lubricating oil product is supplied to the still throughfconne'ction 26 and the residualfoil from which thelubricating oil fraction has beenvaporized'Yis discharged from the still through connection 27. Vapors from the'still 33 escape through valve 28and connection 29 to and through the refining tower 35.: Viv

pors escaping from the refining tower'35,

.sure by means of the pressure reducing valve 287 and theexhaustmg pump 38. Pump 31 1s provided "forthe discharge of condensate through connection 30, are condensed in the v throughconnection 32 when the receiver 37 is under sub-atmospheric pressure. Any material liquefied in thereiining tower is run to a storage tank 39 by means of pump 40, either directly through connection 41 or through cooler a2. 7 The vapors supplied through connection 29may be passed either upwardly or downwardly through refining tower 35 by ineansof the branch connections shown between tower 35 and connections 29 and 30. A charge of an adsorptive catalyst,

for example,-fullei"s earthof -60 or -80 mesh is supported upon a foraminous partition 43 adapted to retain the adsorptive catalyst but to permit free passage of vav pors in the refining tower 35.

27, and the lubricating oil vapors as. driven off are passed through the refining tower 35 where they are sub]ected to refining treatment, in accordance with the invention, un-' 'der sub-atmospheric pressure.

The following example will illustratethis mode of operation; After the still 33 hasv been brought to an'operating balance in the usual way, the vapors of the desired lubricat ing oil-fraction are'driven oil through connection 29 and these lubricating oil vapors are passed through the fullers earth in the refining tower 35 under sub-atmospheric pressure maintained by the operation of the exhaust-ing pump 38 and controlled by regulation of pressure reducing valve 28. The vapors of thelubricating oil escaping from p the refining tower 35 are condensed in the not condenser 36 to form a lubricating oil prodischarged through connection 32. The refining operation proper is, like the :distill ing operaton, carried out continuously.

1 Ifthe lubricating oil stocktreated inthe manner just described contains wax, the discharged lubricatingv oil product is put through filter presses for the separation of such wax. Aga-in this mode of operation makes possiblethe production of finished lubricating oil products from wan-containing stocks without re-running of a diluted stock and without anynecessity of subject ing the oil to mild cracking as that operation is carried out in so-called coke stills because of the conversion of potentially amorphous topotentially crystalline wax.

It is common practice, at present, to fractionate crude petroleum or topped crude petroleuinby passing the oil continuously througha series ofstills, progressively heavier fractions being taken off from each succeeding still of the series. This invention may be employed with particular advantage in conjunction with the operation of these stills of such series from which lubricating oil fractions are taken off without interfering with the operation of the still battery. As applied to such operations, the stills from which lubricating oil fractions are taken off are operated. under the normal operating pressures and the pressure on the lubricating oil vapors separated insuch stills is reduced after the vapors leave the stills.

It will be understood that the usual measuring instruments, such as thermometers and pressure gauges, for example the pressure gauges 44:, 45, 46 and 4;7, are provided as desired or necessary to facilitate observation and control of the op'eration. 7 Likewise, the apparatus usedis with advantage thermally insulated or lagged to minimize heat loss. In particular, the apparatus including the refining receptacle and the vapor connections between the pressure" reducing valve (16 or 28) and the condenser (6 or 36) is advantageously lagged or thermally insulated.

Fullers earth is aparticularly advantageous adsorptive catalyst for use in carrying out the :invention. Other adsorptive 'catalysts useful in carrying out the invention in clude silica gel and otheradsorbent earth and claysr f The invention includes the refining operation proper which has been described comprising the passage of lubricating oil vapors through an adsorptive catalyst such as fullers earth under pressure substantially less than atmospheric pressure, under pressures belowabout20 inches of mercury absolute.

Iclaimi V .1. In the manufacture of lubricating oils, the improvementswhich comprises vaporizing the lubricating oil from a stock containing the same, then reducing the pressure on the vapors, then passing the vapors through an adsorptivecatalyst under apressure below about 20 inches of mercury absolute, and thereafter condensing the vapors to form the lubricating oil product.

2. In the manufacture of lubricating oils from stocks containing potentially amorphous wax, the improvement which comprises vaporizing the lubricating oil from the raw stock, then reducing the pressure on the lubricating'oil' vapors, then passing the lubricating-oil vapors through an adsorptive catalyst under a pressure below about 20 inches of mercury absolute andthereby con verting potentially amorphous wax to potentially crystallinewax, and thereafter condensing the vapors to formthe lubricating oil product.

absolute.

I In testimony whereof, I have subscribed my name.

FRANK A. APGAR. 

